Locking arrangement for vehicle gearbox

ABSTRACT

A locking arrangement for a vehicle gear box comprises a transverse passage in the gear box housing and intersecting the axes of the gear selector rods. An outside one of the rods has a recess and the remainder of the rods have transverse through bores, the recess, the bores and the passage being in alignment when a predetermined gear ratio is selected. Plungers slidable in the rod bores and members slidable in the passage between the rods are movable by an actuator to lock the rods in the position corresponding to the predetermined ratio.

United States Patent [191 Thornley Dec. 25, I973 LOCKING ARRANGEMENT FORVEHICLE GEARBOX Derek Thornley, Nelson, England Joseph Lucas(Industries) Limited, London, England Filed: Feb. 16, 1972 Appl. No.:226,789

Inventor:

Assignee:

Foreign Application Priority Data Feb. 17, 1971 Great Britain 4,884/71References Cited UNITED STATES PATENTS 5/1953 Backus et al 74/477 UX2,847,871 8/1958 Schick 74/477 Primary Examiner-Milton KaufmanAttorney-John C. Holman et al.

[ ABSTRACT A locking arrangement for a vehicle gear box comprises atransverse passage in the gear box housing and intersecting the axes ofthe gear selector rods. An outside one of the rods has a recess and theremainder of the rods have transverse through bores, the recess, thebores and the passage being in alignment when a predetermined gear ratiois selected. Plungers slidable in the rod bores and members slidable inthe passage between the rods are movable by an actuator to lock the rodsin the position corresponding to the predetermined ratio.

7 Claims, 2 Drawing Figures LOCKING ARRANGEMENT FOR VEHICLE GEARBOX Thisinvention relates to a locking arrangement for vehicle gear box wherebysaid box is locked at a predetermined gear ratio.

According to the invention a locking arrangement for a road vehiclegearbox which includes a housing-and a plurality of spaced parallel rodswhose axes lie substantially in the same plane and which are selectivelyaxially movable in the housing to provide a required gear ratiocomprises a transverse passage in the housing, the axis of said passagebeing perpendicular to the axes of said rods, a recess on an outside oneof said rods and facing an adjacent rod, a transverse bore in each ofthe other rods, said recess, said bores and said passage beingsubstantially aligned when said rods are in a predetermined relativeposition, a plunger slidable in each said bore, said plungers beingdimensioned so as to be able to lie wholly within the circumference oftheir respective rods, a plurality of members slidable in said passage,one-of said members being engageable with said recess, and an actuatingelement with another of the members so that, when said rods are in saidpredetermined relative-positions, said plungers and said members may bemoved simultaneously to lock said rods in said relative positions.

A locking arrangement according to the invention will now be describedby way of example and with reference to the accompanying drawings inwhich:

F 1G. 1 is a section through part of a vehicle gearbox, and FIG. 2 is asection, to a different scale, on line 2-2 in FIG. 1.

The gearbox has a housing within which three selector rods 11, 12, 13are selectively slidable by means of a gear lever (not shown). Rods 11and 12 carry respective selector forks l4, 15 which engage slidablesynchromesh elements (not shown) in a known manner. Rod 13 carries anarm (not shown) which acts in a known manner when rod 13 is moved toselect reverse gear in the box. Each of the rods 11, 12, 13 has anassociated detent 16 which tends to locate the rods in their selectedpositions.

Within the housing 10 is a transverse bore 17 whose axis intersects theaxes of rods 11, 12, 13 at right angles. Rod 11 is formed with a recess18 which faces towards the adjacent rod 12. Rods l2, 13 have transversebores 19, 20 which are positioned such that, when the rods 11, 12, 13are in relative positions which correspond to neutral gear, bore 17,bores 19, 20 and recess 18, are aligned.

Plungers 21, 22 are respectively slidable in bores 19, 20 the lengths ofplungers 21, 22 being such that they can slide wholly within thediameters of the rods 12, 13. Plungers 21, 22 preferably have taperedend so that axial movement of the rods urges the plungers inwardly ofthe rods.

Within the bore 17 lie three balls 23, 24, 25 which are constrained soas to move axially only of bore 17. The diameters of the balls 23, 24,25 are greater than the axial dimensions of the portions of the passage17 in which the respective balls lie so that movement of one of the rods11, 12, 13 relative to the other rods displaces the ball, or balls,adjacent the said one rod into engagement with the rod, or rods,alongside that one rod. The displaced ball, or balls, moreover, displaceany remaining balls, as a result of engagement via the plungers, to lockthe said other rods in position.

An edge cam 26 which is rotatable in association with an ignition switch30 for the vehicle, is engageable with ball 25 to urge the lattertowards rod 13 when the vehicle ignition is switched off.

In use, therefore, if neutral gear is selected and the engine ignitioncircuit switched off, plungers 21, 22 and balls 23, 24, 25 are urgedtowards rod 11, locking all rods, and consequently, the gearbox, in theneutral position, from which they cannot be moved until the ignition isagain switched on.

A further bore 27 extends through rod 13 and carries a plunger 28substantially identical with plungers 21, 22. The position of bore 27relative to bore 20 is such that bore 27 is aligned with bore 17 in thebody 10 when reverse gear is selected. The gearbox may therby, ifdesired, be locked in reverse.

1 claim:

1. A locking arrangement for a vehicle gearbox which includes a housingand a plurality of spaced parallel rods whose axes lie in substantiallythe same plane and which are selectively axially movable in the housingto provide a required gear ratio, comprising a transverse passage in thehousing, the axis of said passage being perpendicular to the axes ofsaid rods, a recess on an outside one of said rods and facing anadjacent rod, a transverse bore in each of the other rods, said recess,said bores and said passage being substantially aligned when said rodsare in a predetermined relative position, a plunger slidable in eachsaid bore, said plungers being dimensioned so as to be able to liewholely within the circumference of their respective rods, a pluralityof members slidable in said passage, one of said members beingengageable with said recess, an electric switch forming part of anignition circuit for the vehicle, and an actuating element operated bysaid switch and engageable with another of the members so that, whensaid rods are in said predetermined relative position, said plungers andsaid members may be moved simultaneously by operation of said switch tolock said rods in said relative position. v

2. A locking arrangement as claimed in claim 1 in which the dimensionsof said members, axially of the passage, is greater than the axialdimension of that portion of the passage in which the respective membersare slidable.

3. A locking arrangement as claimed in claim 1 in which the oppositeends of said plungers are chamfered.

4. A locking arrangement as claimed in claim 1 in which said memberscomprise balls.

5. A locking arrangemement as claimed in claim 1 in which said actuatingelement comprises a cam.

6. .A locking arrangement as claimed in claim 5 in which said cam is anedge cam engageable with a one of said members which is furthest remotefrom the said outside one of the rods.

7. A locking arrangement for a vehicle gearbox which includes a housingand a plurality of spaced parallel rods whose axes lie in substantiallythe same plane and which are selectively, axially movable in the housingto provide a required gear ratio, comprising a transverse passage in thehousing, the axis of said passage being perpendicular to the axes ofsaid rods, a recess on an outside one of said rods and facing anadjacent rod, a transverse bore in each of the other rods, said recess,

said plungers and said members may be moved simultaneously to lock saidrods in said relative positions, a further bore in one of said rods anda plunger slidable in said further bore, said further bore being spacedaxially of the rod from the first-mentioned bore in the rod, wherebysaid rods may be locked in a further relative position.

1. A locking arrangement for a vehicle gearbox which includes a housingand a plurality of spaced parallel rods whose axes lie in substantiallythe same plane and which are selectively axially movable in the housingto provide a required gear ratio, comprising a transverse passage in thehousing, the axis of said passage being perpendicular to the axes ofsaid rods, a recess on an outside one of said rods and facing anadjacent rod, a transverse bore in each of the other rods, said recess,said bores and said passage being substantially aligned when said rodsare in a predetermined relative position, a plunger slidable in eachsaid bore, said plungers being dimensioned so as to be able to liewholely within the circumference of their respective rods, a pluralityof members slidable in said passage, one of said members beingengageable with said recess, an electric switch forming part of anignition circuit for the vehicle, and an actuating element operated bysaid switch and engageable with another of the members so that, whensaid rods are in said predetermined relative position, said plungers andsaid members may be moved simultaneously by operation of said switch tolock said rods in said relative position.
 2. A locking arrangement asclaimed in claim 1 in which the dimensions of said members, axially ofthe passage, is greater than the axial dimension of that portion of thepassage in which the respective members are slidable.
 3. A lockingarrangement as claimed in claim 1 in which the opposite ends of saidplungers are chamfered.
 4. A locking arrangement as claimed in claim 1in which said members comprise balls.
 5. A locking arrangemement asclaimed in claim 1 in which said actuating element comprises a cam.
 6. Alocking arrangement as claimed in claim 5 in which said cam is an edgecam engageable with a one of said members which is furthest remote fromthe said outside one of the rods.
 7. A locking arrangement for a vehiclegearbox which includes a housing and a plurality of spaced parallel rodswhose axes lie in substantially the same plane and which areselectively, axially movable in the housing to provide a required gearratio, comprising a transverse passage in the housing, the axis of saidpassage being perpendicular to the axes of said rods, a recess on anoutside one of said rods and facing an adjacent rod, a transverse borein each of the other rods, said recess, said bores and said passagebeing substantially aligned when said rods are in a predeterminedrelative position, a plunger slidable in each said bore, said plungersbeing dimensioned so as to be able to lie wholly within thecircumference of their respective rods, a plurality of members slidablein said passage, one of said members being engageable with said recess,an actuating element engageable with another of the members So that,when said rods are in said predetermined relative positions, saidplungers and said members may be moved simultaneously to lock said rodsin said relative positions, a further bore in one of said rods and aplunger slidable in said further bore, said further bore being spacedaxially of the rod from the first-mentioned bore in the rod, wherebysaid rods may be locked in a further relative position.